I Chronicles 5:1 Now the sons of Reuben the firstborn of Israel, (for he was the firstborn; but, forasmuch as he defiled his father’s bed, his birthright was given unto the sons of Joseph the son of Israel: and the genealogy is not to be reckoned after the birthright.
Reuben was the firstborn. He should have gotten the birthright. He sinned against his dad by defiling his bed. Due to his sin he lost the privilege that was his. The birthright passed on to Joseph and his sons.
He did not quit being his dad’s son. He did not lose his sonship but he did lose the blessing and privilege of the birthright.
You will not lose your sonship by sin but you can lose privileges here in the earth. God has blessings for you here on this earth that you might lose by sin. Let’s be careful not to lose such great privileges.